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HER2 Gene Amplification Assay by FISH

C-erb B-2, HER2 FISH, PathVysion, HER2 Amplification Test (FISH), FISH for Breast Cancer

Department

Advanced Diagnostics

Specimen Collection Criteria

Collect (preferred specimen): Formalin-fixed, paraffin-embedded block with corresponding H&E slide. Tissue should be well fixed and well processed. 

Also acceptable: One H&E slide plus 4 unstained tissue sections cut at 4 µm thickness and placed on charged slides. Oven dry at 60°C for 1 hour. Unbaked or air-dried slides are acceptable. Tissue adherence cannot be guaranteed for sections placed on plain glass slides. Send all slides within 6 weeks of cutting. 

All specimens must be accompanied by a completed requisition containing the patient name, date of birth, collection date, ordering physician, source of specimen, fixation time and cold ischemia time (if known), and a pathology report.

Physician Office/Draw Specimen Preparation

Maintain paraffin-embedded tissue or slides at room temperature (20-25°C or 68-77°F) until transport. 

Preparation for Courier Transport

Transport: Paraffin-embedded tissue or slides, at room temperature (20-26°C or 68-78.8°F). 

Rejection Criteria

• Tissue in fixatives other than 10% formalin.
• Improper labeling, inadequate information.
• Decalcified specimens.

Inpatient Specimen Preparation

Please refer to Surgical Specimen, Routine in the Beaumont Laboratory Test Directory.

In-Lab Processing

Maintain specimens at room temperature (20-26°C or 68-78.8°F) until testing.

Storage

Specimen Stability for Testing:

Paraffin-Embedded Tissue
Room Temperature (20-26°C or 68-78.8°F): Indefinitely 
Refrigerated (2-8°C or 36-46°F): Unacceptable 
Frozen (-20°C/-4°F or below): Unacceptable 

Tissue Section on Glass Slides
Room Temperature (20-26°C or 68-78.8°F): 6 weeks 
Refrigerated (2-8°C or 36-46°F): Unacceptable 
Frozen (-20°C/-4°F or below): Unacceptable 

Specimen Storage in Department Prior to Disposal:

Freezer (-20°C or -4°F) 6 weeks 

Laboratory

Royal Oak Anatomic Pathology – Advanced Diagnostics Laboratory.

Performed

Daily. Results available in 5-7 days.

Reference Range

HER2 neu is considered positive in Groups 1, Group 2 AND concurrent IHC 3+, Group 3 AND concurrent IHC 2+ or 3+, Group 4 AND concurrent IHC 3+.

HER2 neu is considered negative in Group 2 AND concurrent IHC 0-1+ or 2+, Group 3 AND concurrent IHC 0-1+, Group 4 AND concurrent IHC 0-1+ or 2+, or in Group 5.

Groups are defined as such:
Group 1: Ratio >=2.0 >=4.0 signals/cell,
Group 2: Ratio >=2.0 <4.0 signals/cell,
Group 3: Ratio <2.0 >=6.0 signals/cell,
Group 4: Ratio <2.0 >=4.0 and <6.0 signals/cell,
Group 5: Ratio <2.0 <4.0 signals/cell. 

Test Methodology

Fluorescent in situ Hybridization.

Interpretation

Hybridized sections are reviewed on a fluorescence microscope by a trained Molecular Technologist. The ratio of amplification is determined using a computer assisted algorithm. Results are reviewed by the pathologist who will provide an interpretive report.

Results are reported as Not Amplified (HER2 neu is considered positive in Groups 1, Group 2 AND concurrent IHC 3+, Group 3 AND concurrent IHC 2+ or 3+, Group 4 AND concurrent IHC 3+. HER2 neu is considered negative in Group 2 AND concurrent IHC 0-1+ or 2+, Group 3 AND concurrent IHC 0-1+, Group 4 AND concurrent IHC 0-1+ or 2+, or in Group 5).

Amplified (Groups are defined as such:
Group 1: Ratio >=2.0 >=4.0 signals/cell,
Group 2: Ratio >=2.0 <4.0 signals/cell,
Group 3: Ratio <2.0 >=6.0 signals/cell,
Group 4: Ratio <2.0 >=4.0 and <6.0 signals/cell,
Group 5: Ratio <2.0 <4.0 signals/cell)

Clinical Utility

HER2 gene amplification has been associated with a shorter disease-free interval and shorter overall survival. Women who have tumors with HER2 gene amplification are most likely to be responsive to monoclonal antibody therapy directed against this target. 

Reference

1. Wolff AC, Hammond MEH, Hicks DG, et al. American Society of Clinical Oncology/College of American Pathologists Guideline Recommendations for Human 
   
   Epidermal Growth Factor Receptor 2 Testing in Breast Cancer. J Clin Oncol 2013 Nov 1; 31(31) 3997-4013. 

CPT Codes

Technical: 88366, 88374 (Automated). 

Professional: 88366, 88374 (Automated).

Contacts

Last Updated

9/29/2022